Dilychnia cavicollis, OLIVIER, 1912

Vaz, Stephanie, Mermudes, José Ricardo M., Paiva, Paulo C. & Da Silveira, Luiz Felipe L., 2020, Systematic review and phylogeny of the firefly genus Dilychnia (Lampyridae: Lampyrinae), with notes on geographical range, Zoological Journal of the Linnean Society 190, pp. 844-888 : 875-876

DILYCHNIA CAVICOLLIS OLIVIER, 1912

( FIGS 11, 27)

Dilychnia cavicollis Olivier, 1912: 171 ; McDermott, 1966: 73 (cat.).

Lucidota cavicollis Blackwelder, 1945: 354 (cat.).

Type material: Holotype examined, male ( MNHN) ( Fig. 27A). Labels: Dilychnia cavicollis Ern. Oliv. [green label]; male symbol [light brown label] ( Fig. 27B).

Diagnosis: Male antennomere III three-quarters of length of scape ( Fig. 11C); elytra lateral margin subparallel ( Fig. 11A); sterna VI and VII bearing complete light organs with lateral margin emarginate ( Fig. 11G); sternum VIII posterior margin with median region acuminate, reaching one-half of height of sternum ( Fig. 11I); pygidium lateral margin acute and posterior margin with median region acuminate ( Fig. 11H); paramere apex with long and rounded projection ( Fig. 11N); and phallobase symmetrical, with posterior margin with median region emarginate ( Fig. 11M).

Colour pattern: Frons and antenna black, mouthparts dark brown ( Fig. 11F); pronotum with posterior margin Aedeagus: Phallobase slightly emarginate ( Fig.11M–O); parameres acute towards apex; phallus with dorsal plate sinuose ( Fig. 11M); ventral plate strongly sclerotized ( Fig. 11O).

and region over the head orange, and anterior and lateral margins yellowish ( Fig. 11D); scutellum light brown, elytron dark brown with lateral and external orange bars ( Fig. 11A); pro- and mesoleg with femur orangish yellow, tibia and tarsus black, metaleg black ( Fig. 11C); abdomen almost completely black, and sternum VIII light brown ( Fig. 11C).

Head: Antenna filiform, covered with short setae ( Fig. 11C); scape as wide as antennomere III ( Fig. 11C). Maxilla with palpi four-segmented: I small and triangular; II 2× longer than I, triangular; III triangular and 2× longer than II; and IV stout, subtriangular and 2.5× longer than III. Labium with palpi three-segmented: I and II subequal; and III securiform.

Thorax: Pronotum semicircular, slightly projected anteriad, slightly wider than long, anterior and lateral margins strongly concave, posterior margin with median region indented and posterior angles projected, obtuse ( Fig.11D);hypomeron trapezoidal, 3× wider than long and median region projected ( Fig. 11E); scutellum rhombus shaped, acute posteriad ( Fig. 11A); elytra slightly convex, with lateral margin subparallel ( Fig. 11A); metafemur slightly thinner than pro- and mesofemora. Tarsomere I with lateral margin straight and 2× longer than II, pro- and mesotarsomere dorsally indented; II 1.5× longer than III; III triangular; claws simple.

Abdomen: Sterna lateral margin divergent posteriad, posterior angles straight ( Fig. 11C); sterna VI and VII median region with light organ complete with slightly indented lateral margin ( Fig. 11G); sternum VIII slightly wider than long ( Fig. 11I); pygidium as wide as long, sclerotized, posterior margin with two parasagittal emargination and median region acuminate ( Fig. 11H); and sternum IX with posterior margin slightly emarginate ( Fig. 11J–L).

Female: Pronotum one-third wider than long; sternum VI median region with rectangular light organ with posterior angles rounded, covering two-thirds of width of the sternum; sternum VII median region with light organ semicircular; sternum VIII with sinuous lateral margins, converging posteriad, and posterior margin with median region indented; p y g i d i u m p o s t e r i o r m a r g i n w i t h p a r a s a g i t t a l sinuosities, posterior angles acute, and a median region acuminate.

Remarks: This species can be distinguished from others by its colour pattern, its median region orange pronotum and yellow anterior and lateral margins, the dark brown elytron with outer and inner lateral orange bars ( Fig. 11A), filiform antennomeres III –XI ( Fig. 11B, C), sternum XI with emarginate posterior margin ( Fig. 11J–L) and a male aedeagus with an emarginate phallobase ( Fig. 11M–O).

Material examined: BRAZIL: Goiás: Jataí, Fazenda Aceiro, 1 male, X.1962, Expedição Departamento de Zoologia ( MNRJ) ; São Paulo: Ribeirão Preto , 1 male, XI. 1954, Barretto ( MZSP) , São José do Rio Pardo , 10 males and 6 females, XII. 1998, Gounelle ( MNHN) .